Safety-valve.



No. 780,414. PATENTED JAN. 17, 1905.

J. W. DUNCAN.

SAFETY VALVE.

APPLICATION BIL ED MAY 21. 1904.

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UNITED STATES JOHN W. DUNCAN, OF HOUTZDALE, PENNSYLVANIA, ASSIGNOR OF TWO- THIRDS TO LUTHER 0. AND GEORGE PENNSYLVANIA.

Patented January 1 7, 1905/ PATENT OFFICE.

SAFETY-VALVE.

SPECIFICATION forming part of LettersPatent N0. 780,414, dated. J'anuary17, 1905.

v v Application filed. May 21, 1904:. Serial No. 209,037;

To aZZ whom, it roe/my concern: 2

Be it known that I, JOHN W. DUNCAN, a citi- Zen of the UnitedStates, and a resident of Houtzdale, in the county of Clearfield and State of Pennsylvania, have invented a new and useful Improvement in Safety-Valves, of which the following is a specification.

My invention relates to improvements in safety-valves for steam-engines, the objects being to provide a valve of this nature which will be self-regulating and one which will operate under all circumstances inthe event of an accident resulting in the breakage of the steam-conveying pipe to instantly and automatically close the pipe against the further entrance of steam thereto,in this manner 'absolutely preventing the scalding of the engineer or others who may be near the engine.

To these ends my invention consists, primarily, of a steam-chamber connected with the boiler and with the engine-cylinders, the steam-chamber being provided with a regulating or engine port and having a suitablysupported valve-rod located within the chamber, the valve-rod provided with a pistonvalve adapted to control the feed" of steam to the cylinders through the regulating or engine port.

My invention further consistsin certain other novel details of construction and con1- binations of parts which will be more fully described hereinafter andparticularly pointed out in the claims.

The accompanying drawing is a view in side elevation of my improvement, parts being shown in full lines and broken away in order to better disclose the invention.

A indicates the steam valve-chamber, with which a large conduit 1 from the boiler or other suitable steam-supply connects, the con duit being provided with a flange 2 for attachment to the boiler.

The steam or valve chamber A is provided.

at one end with a removable plug 3,. having a regulating piston-bearing 1 formed therethrough and leading to the atmosphere, the

inner end of the regulating piston-bearing being surrounded by a seat 5, the plug itself provided with lugs 6 6 to facilitate its placing vided with-aflangelO, to which the flange 11 of the steampipe 8 is secured, the pipe 8 being provided with a suitably-packed box 12, in which a gate-valve 13 is received, the gatevalve being manually operated in anysuitable way, as by means of the screw and wheel shown, the lower end of the gate-valve re ceivable within a seat 14, formed in the pipe 8.

The steam-chamber A is adapted to receive a double piston-valve consisting of a large valve-head 15, adapted to control the steamport 7 and receivable on the seat 9, and the smaller cylindrical piston-valve 16. received within the regulating piston-bearing 1 and having a head 17 received upon the seat 5. The piston 16 is adapted to snugly fit the bearing to make the bearing as nearly steam-tight as possible. r 7

Extending between and connecting the valve-disk l5 and piston 16 is a valve or piston W, WARRIOK, OF HOUTZDALE, I I

rod 18, one end of which passes through the packing-rings forming the piston-valve 16 and is squared at its outer end to permit the valve and piston to be rotated or turned to prevent sticking in their seats. The piston 16 serves as a guide and support for the valverod at that end, the valve-head 15 at the opposite end of the valve-rod being provided witha plurality of spaced pins 19, extending into the steam-port 7 to guide and support the valve. The area of the conduit 1, communicating with the steam or valve chamber A, is larger than the steam-port, and the valvedisk 15 is provided with a balance-port 20 extending therethrough to permit the passage of steam in order that a balanced pressure may be obtained on each side of the disk when the gate-valve is closed.

The operation of my device is as follows: Steam is gotten up in the boiler to, say, one

hundred and twenty-five pounds pressure,

which pressure, of course, is the same in the steam-chamber A, to which the boiler is connected by conduit 1, and is exerted against both valve-disk 15 and piston 17, and, novided the gate-valve 13 is open, the valve 15 will be closed and the valve 17 opened, owing to the fact that the valve-disk 15 is of larger area than is the piston-head 17. Therefore in starting the engine it is necessary that the gate-valve 13 be closed, in which event the steam passing through the balance-port 20 will create an equal pressure on each side of the large valve-disk 15, thereby permitting the pressure on the inside face of the smaller piston-head 17 to move the valve-stem and valve-disk away from the steam-port 7 'and permitting access of the steam to the engine. In the event that the steam-conveying pipe 8 is broken at a point beyond the gatevalve 13 the steam will, of course, immediately exhaust through such opening, relieving the pressure on the regulating-piston 17, but exerting a pressure on the larger valve 15, which is thereby closed, the piston sliding in its bearing 4 until the valve-disk 15 is firmly received in its seat 9. The gate-valve 13 is then lowered, whereupon the steam creates a balanced pressure on each side of the valve 15, which results in opening the valve 15 and moving the regulating-piston outward in its bearing until the piston-head 17 is received firmly in the seat 5, the steam-pressure exerting itself against the gate-valve, which may be slowly opened as soon as the break is mended to permit the engine to again work at its full capacity.

It will be observed that no springs are used in my construction, that my construction is simply and easily constructed, that it can be placed upon the market cheaply, and that by its use many accidents and loss of lives will be prevented.

The breaking of a large pipe on a boiler carrying two hundred pounds pressure or more causes a sudden reduction of pressure, and the water being heated to 100 or more above the steam-forming point will immediately flash into steam and burst the boiler itself; but by means of my improvement such sudden reduction of steam-pressure is prevented. It is obvious that many changes might be made in the form and arrangement of the several parts described without departing from the spirit and scope of my invention, and hence I do not wish to limit myself to the exact construction herein set forth; but,

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. A mechanism of the character set forth comprising a steam-chamber communicating with a suitable steam-supply,the chamber provided with an engine-port and a regulating piston-bearing, a piston-valve opening and closing the engine-port, a piston received in and permanently closing the bearing and a piston-rod connecting the valve and piston, the rod being of less length than the distance between the port and bearing in order that the regulating-piston may open the enginevalve.

2. In a safety-valve mechanism, the combination with a steam-chamber communicating with a suitable source of supply and provided with an engine-port and a regulating pistonbearing leading to the atmosphere, of a valve for controlling the port, a piston in the bearing, the engine-port valve being larger than is the piston and means connecting the alves to open and close the engine-port.

3. In a safety-valve mechanism, the combination with a steam-chamber communicating with a suitable supply, and also provided with a large engine-port and a smaller piston-bearing opposite and in alinement with each other, of a large valve seating in or unseating from the engine-port and a smaller piston closing the piston-bearing, and means extending between and connecting the valve and piston for opening and closing the valve.

4. In a safety-valve mechanism, the combination with a steam-chan'iber in COIDIIILIDlClL- tion with a suitable source of supply and provided with an engine-port and a piston-bearing leading to the atmosphere, of a valve controlling the engine-port, a piston constantly closing the bearing, and means connecting the valve and port to open and close the valveport only.

5. In a safety-valve mechanism, the combination with a steam-chamber communicating with a suitable source of supply, and provided with an engine-port and a piston-bearing leading to the atmosphere, a valve controlling the engine-port, a piston sliding in the bearing, means connecting the valve and piston, a gatevalve, and means for balancing the pressure on each side of the engine-port valve when the gate is closed.

6. In a safety-valve mechanism, the combination with a steam-chamber communicating with a suitable source of supply, of a plug removably secured to and closing one end of the steam chamber, the plug provided with a piston-bearing passing therethrough from the chamber to the atmosphere, the steam-chamber also provided with an engine-port, a piston in the bearing, a valve controlling the engine-port, and means extending between and connecting the valve and piston to open and close the engine-port.

7 In asafety-valve mechanism, the combination with a steam-chamber communicating with asuitable source of supply, and provided with a piston-bearing, of a pipe leading from the steam-chamber, a valve controlling the entrance of steam to the pipe, a gate-valve in the pipe, the first-named valve provided with an aperture therethrough to equalize the pres- 8. In a mechanism of the character de-' scribed, the combination with a steam-chamber provided with an outlet-port leading to an engine, and a piston-bearing leading to the atmosphere, of seats formed adjacent the port and the bearing, a valve receivable in the seat adjacent the port, a'piston received in the bearing, a piston-head carried by the piston and adapted to engage the seat adjacent the bearing, means connecting the valve and piston, the seats limiting the movement of the valve and piston in opposite directions and supporting and guiding means carried by the valve and received in the port.

9. In a safety-valve mechanism, the combination witha steam-chamber communicating with a suitablesource of supply, of a pipe leading from the chamber, a valve-seat formed in the pipe, a sliding manually-operated valve receivable in the seat to close the pipe, the steam-chamber provided with a piston-bearing communicating with the atmosphere, a piston sliding in and completely closing the bearing, and with a port leading to the pipe, a'valve closing and opening the port, and means connecting the valves, the valve controlling the entrance of steam to the pipe being provided with an equalizing-aperture.

10. In an automatic safety mechanism of the character described, .the combination with a steam-chamber provided with a piston-bearing leading to the atmosphere and an engine-port,

of a valve-stem, a valve carried at one end of the stein for opening and closing the port, a piston carriedat the opposite end of the stem, the piston received in the bearing, the valvestem protruding through the bearing to provide means for loosening the valve and piston to prevent sticking the length of the stem between the valve and piston being less than the distance between the port and bearing.

11. A safety valve comprising a steamchamber connected with a suitable source of supply, the steam-chamber provided with a valve-port and a piston-bearing leading to the atmosphere, a valve opening and closing the valve-port, a piston snugly fitting in the piston-bearing and a piston-rod connecting the piston and valve and of less length than the distance between the ports.

12. .Amec'hanism of the character set forth comprising a steam-chamber communicating with a suitable steam-supply, the chamber provided with an engine-port and a regulating piston-bearing, a single piston-valve controlling the engine-port, a piston received in and permanently closing the piston bearing against the passage of steam and a piston-rod connecting the valve and piston.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

JOHN IV. DUNCAN. Witnesses:

J NO. B. MOGRATH, CHAS. T. KINNEY. 

